This is the most popular mod for the TKM-707. It opens the transmit capabilities to cover the entire HF spectrum (1.6 to 30 MHz continuous) rather than just marine channels. This is often called the MARS/CAP mod because it allows operation on Military Affiliate Radio System frequencies.
Goal: Increase PEP output beyond 150W.
Method:
Warning: PA transistors (2SC2879, etc.) are easily destroyed above 180–200W. Not recommended. Kenwood Tkm-707 Mods
Goal: Increase average talk power.
Method (if factory-disabled):
Result: +6 dB perceived loudness but higher distortion. This is the most popular mod for the TKM-707
The stock TKM-707 has decent audio, but it’s optimized for narrow marine voice (2.4 kHz). Hams prefer a slightly richer transmit audio profile.
The TKM-707 is a 50-watt radio, which is excellent for mobile use but can be overkill for home use or a drain on a vehicle’s electrical system if not managed properly.
The Kenwood TKM-707 is a legend. Built like a tank for the marine market, it has found a second life in the shacks of amateur radio operators who crave a rugged, high-performance HF transceiver. Why? Because it shares DNA with the famous Kenwood TS-450, but you can often pick one up for a fraction of the price. Warning: PA transistors (2SC2879, etc
However, the TKM-707 came out of the box with maritime restrictions. To make it sing on the ham bands, you need to perform a few key modifications.
Disclaimer: These modifications are intended for licensed amateur radio operators only. Transmitting out of band is illegal and can result in hefty fines. Proceed at your own risk.
Here are the top three mods every TKM-707 owner should know about.